Hull sheathing

The new hull has now been sheathed in 6mm marine plywood.  This entailed making eight scarf joints.  A 9/1 scarf slope was used with all panels being beveled using a hand plane.  For me at least, the hardest part of beveling the scarfs seems to be to hold the plywood absolutely flat.  Thin plywood has a tendency to bow slightly either up or down, so I built an 8-foot jig and used multiple clamps to hold the plywood straight and level.  Four of the scarf joints (the short pieces) were bonded on the jig and four were bonded on the hull itself with equally successful results.  I did not want to try to position, epoxy bond, and clamp 19-foot panels by myself on the hull frame.

The hull was designed with flat cross-sectional panel sections located eight feet from the stern with backing plates (3/4" lumber) for the future joining of fore and aft panels.  That way I was able to split the sheathing task into forward 11-foot panels and aft 8-foot panels.   Each piece needs to be positioned precisely after being pre-coated with fresh epoxy; it needs to be done somewhat quickly so that the epoxy is still in an easily flowable and penetrating state, and then cleanup to remove squeeze-out and drips needs to be completed.  Especially at the hull forefoot and topside stern tumblehome, the panels need to easily bend to significant curvatures.

Thus, these panels were soaked in a shallow basin of water for two hours and then temporarily clamped in place until they dried out.  In this way they adopted a pre-warp to more easily conform to the curvature and required much less clamping force when permanently bonded.  The plywood sheathing will provide the foundation for the next layer of hull coating, 5mm thick planking.  This will be followed by fiberglass cloth and more epoxy resin.

The origin of the "Boat Bowl"

A few months ago, my wife showed me a picture of a wooden bowl from a catalog and asked me if I could create something similar. I had a concept in my mind that I thought I would try "someday", so this was the opportunity to use it. I quickly drew and fabricated a bowl to prove the technique. It came out okay, so I made some bowls slightly bigger, realizing that bigger was actually easier when laminating and sanding the inside. Then she asked for a longer, more flared design, and I made several of those, including for a friend who liked the design. Well, as one who enjoys designing and building boats, you may guess what happened next. I took the design for the next boat I plan to build and simplified and scaled it to create a "boat bowl".

Another year, another boat

A new boating season is beginning, and it is time to recharge the battery, refill the gas tanks and get out on the water.  However, after last season I thought of all the ways I could learn and improve from my last boatbuilding experience and create an even better design.  I wanted something of the same size but more closely resembling a classic runabout and with a better integrated sun shade.  After calculating the offsets and sketching out the results, I started drawing out full-size patterns.

At about Christmas, I started putting together wooden frames.  By themselves, the frames look like just a pile of wood scraps, but when you mount them on a strongback, align them using a laser, and start adding the keel and other longitudinal members, it begins to look like a boat.  With the experience of building something similar, I have been able to move forward more confidently this time.  Instead of searching for answers, I know how to handle the design and construction challenges at each step.  Having purchased a new table saw has been a great help also.

I am now ready to make patterns for the exterior sheathing.  The 6mm marine plywood will arrive soon.  I hope to finish the sheathing (plywood, cypress planking, glass and epoxy) and sanding during the summer months when I can leave the windows open.  Next fall will be time for an upholstered interior and other finishing details.  Changes from the previous design include a constant deadrise (12 degree) hull bottom, chine flats, a straight sheer profile with the foredeck raised 5 inches, and reduced deck camber.  This hull is meant for slightly more power / higher speed.